Appliances can include a light emitting device to transmit visual information to a user or to provide illumination within a chamber. The light emitting device can be a light emitting diode, a liquid crystal display, or other type of device that includes an element having a light intensity. The luminescence or light intensity level of the light emitting device can depend on various factors such as driving current or voltage. When the light emitting device is a light emitting diode (LED), driving the LED at a high current in a high temperature environment causes premature damage to the light emitting device.
Conventionally, light emitting devices in a display or an appliance chamber can include LEDs that are driven using a static direct drive where the current or voltage remains constant to achieve a light intensity level. A light emitting device including a LED is illumined at less than full intensity to prevent premature damage to the LED at higher temperatures. This causes the light intensity to be maintained at a low level, making it difficult for a user to read the display or see within the chamber. Increasing the light intensity level causes the premature damage to the LED because the component temperature increases as the current and voltage are increased to reach the higher light intensity level.
In another conventional approach, light emitting device in a display including a LED can be driven using a variable current. A temperature directly surrounding the LED can be detected and the light emitting diode can be driven based on the temperature detected in the area surrounding the device. However, this method increases the complexity of the detection and driving circuits and also increases the cost of the device.
While various methods for protecting light emitting diodes based on temperature are known, a need exists for an improved method of controlling a light intensity of a light emitting device in an appliance. A method of variably controlling the light intensity of the light emitting device in the appliance based on current operating conditions such as a temperature value in a chamber of the appliance would be useful. An appliance capable of increasing the light intensity while protecting the reliability of the light emitting device and adapting to various operating conditions would also be particularly useful.